The underlying invention generally relates to the field of markup languages used to describe adaptive mobile multimedia applications and/or presentations being inherently dependent on the continuously changing environment they are running in, which means that these mobile multimedia applications and/or presentations need to be adapted to the preferences of mobile users, the capabilities of their mobile computing devices, and the users physical impact like current location, time or temperature.
Applications running on mobile devices are experiencing a highly dynamic environment. They have to cope with inherent fluctuation of the available Quality of Service (QoS) in wireless networks, and they should be usable on a wide range of different devices. Additionally, for providing a good service, they should take the users' preferences and context into account, e.g. his current location. To meet those requirements, the developers of such applications need to be supported by a platform that allows applications to adapt to different networks, device and user situations, and which hides some of the complexity involved. Adaptive Multimedia Support Environment (AMUSE) is a platform, which supports adaptive distributed multimedia retrieval applications. The platform consists of three parts, a client-side middleware, a multimedia application built on top of the middleware, and a server-side context-aware mobile portal.
By contrast, the focus of the underlying invention is the document-based approach in the way that adaptive mobile applications and/or presentations are described with an XML-based document, generated by a server-side authoring system (represented by the context-aware mobile portal), processed and rendered by client-side middleware, capable of executing the processing of the XML-based document description.
There are different ways to realize multimedia applications. First, a multimedia application can be quite specific, implemented for a specifically defined scenario, and the application itself might be adjustable by a configuration file, which is quite good for a specific, narrowed scenario. The second way would be to describe a multimedia application in a document-based way and let a browser or player interpret the document, which is done e.g. in “Synchronized Multimedia Integration Language” (SMIL, cf. SMIL 2.0, W3C Recommendation, 7 Aug. 2001, http://www.w3.org/TR/smil20/), and is a more general approach. In the scope of the underlying invention, the latter has been applied. Thereby, multimedia document models such as Hypertext Markup Language (HTML), Dynamic HTML (DHTML), Multimedia and Hypermedia Information Coding Expert Group (MHEG, cf. International Organization for Standardization, ISO/IEC JTC1/SC29/WG12, http://www.mheg.org/), SMIL and HyTime (cf. Users' Group Home Page www.hytime.org) have been evaluated in order to use or extend their document models for describing adaptive multimedia applications. Unfortunately, these document models do not provide sufficient modeling support for adaptive applications. Adaptation is addressed to some extend once at start-up time of a multimedia application, but mobile adaptive multimedia applications have additional adaptation requirements owing to the inherent dynamic environment they are running in. Selecting appropriate streaming media at start-up time does not consider changes, like fluctuation of QoS in wireless network during the run-time of an application.
Applications running on mobile devices are experiencing a highly dynamic environment. The environmental changes can be categorized into three different dimensions: network QoS, mobile device capabilities, and user context. A mobile application has to cope with changes in all three dimensions. Thereby, the term “situation” is used for a given network QoS, mobile device capabilities and user context. A situation can be characterized by a set of parameters describing different aspects of the environment. The “current situation” is the situation, which exists at present for a mobile application. If the current situation causes a problem for the application or if it allows the application to improve its service, the application may change its behavior to better reflect said current situation. As this is true for all mobile applications, the situation is especially interesting when looking at multimedia applications, as those have very tough requirements, especially concerning Quality-of-Service (QoS) conditions of the applied network.